WirelessHD is a wireless video area network (WVAN) specification that provides an interface for wireless high-definition (HD) transmission of video, audio, and data signals over short distances for consumer and commercial electronics products. In a primary application WirelessHD replaces a wired connection, such as an HDMI (High Definition Multimedia Interface) connection between a source, such as s set-top box, disk player, internet appliance, or camera, and a sink, such as a display or a recorder. WirelessHD is available to allow a wall mounted display to receive audio and video from a nearby set of components without any wires. Uncompressed 1080p resolution video with 24 bit color at 60 Hz refresh rates with uncompressed 8 channel audio is supported by WirelessHD for this purpose. Lower resolutions and video and audio only are also supported. However, the high data rates offered by WirelessHD can be used for other wireless networking applications.
WirelessHD allows for beam steering so that the energy of a data stream from a source can be focused on the sink receiver. This also allows for a beam to be steered around obstacles using reflections off walls and other fixtures. Accordingly, a direct line of sight (LOS) connection may be formed or a non-line of sight (NLOS) connection depending on the operating environment. The directional connection can be adapted during transmission through signaling and feedback protocols to meet different environments and changes in those environments. This allows for slow mobility devices to also be used in a WVAN.
The interface has a high rate physical channel (HRP) to carry the primary data traffic for audio visual and high rate devices. Current rates are on the order of a few Gb/s. This channel is typically directional and one-way. The HRP can support different data rates depending on the video or audio resolution being transmitted and also carries some control signaling. The WirelessHD interface also includes a low rate physical channel (LRP) also capable of supporting multiple data rates. The LRP is a two way signal that can be sent omni-directionally and operates on the same or overlapping carriers with the HRP. The LRP carries signaling and control signals as well as low rate data traffic. It has a range of a few Mb/s to 30 or 40 Mb/s. The LRP offers lower power and a more robust radio channel.
The WirelessHD air interface uses OFDM (Orthogonal Frequency Division Multiplexing) with different modulations. The data is encoded and may also be punctured before it is modulated. The unlicensed spectrum around 60 GHz can be used for wireless video transmission or very high-speed networking. More specifically, seven GHz of contiguous bandwidth has been opened for unlicensed use at millimeter-wave frequencies around 60 GHz in the U.S. and Japan
The capability for high date rates and rich control signaling offered by WirelessHD provide great promise for many wireless networking applications. The value of the technologies available in WirelessHD can be increased further by supporting additional streams of HRP and LRP channels to multiple users simultaneously. With careful attention to channel quality, the bandwidth possible for one or more users can be increased well beyond 3 Gb/s. This can allow these technologies to go beyond WirelessHD to many other applications.